Taps are widely used in washrooms of families, hotels, restaurants, or in basins and water tanks of kitchens. People cares more and more about the health, water for cooking, washing fruits and vegetables and drinking needs to be filtered to use. There are taps with filtering function in the market. However, these taps only outlet filtered water. Water for washing products, hands or clothes needn't to be filtered. This kind of filtering tap with single function in long and high frequency usage would shorten the filtering element's service life, resulting in a waste of resource.